Wireless communications devices transporting voice allows multiple parties to remain in contact with one another when deployed in the field. These devices typically use low rate voice encoders (i.e., vocoders) to robustly transmit digital speech to a receiver. On the receive side, low rate voice decoders are used to convert the digital speech back to analog speech.
In noisy environments, the receiving party may have a difficult time hearing the speech message from the transmitting party. This means that the receiving party would have to ask for the speech message to be resent. If the link between the transmitting and receiving party is lost and cannot be reconnected, then the receiving party simply misses out on the speech message. In certain situations the loss of a speech message providing command and control information may be critical. Consequently, there is a need to improve the reliability of the voice link between the transmitting party and the receiving party.
One approach to addressing this problem is disclosed in U.S. Pat. No. 2006/0217159 which provides a wireless communications device that may be selectively operated in one of a voice-to-text operating mode and an audible operating mode. In the voice-to-text operating mode, a speech-to-text converter is used for converting a received speech message to a corresponding text message which is then sent to a display for viewing by the receiving party. Operation in the voice-to-text operating mode may be based on a comparison of a measured ambient noise level and a predetermined threshold. Alternatively, a control signal for selecting the voice-to-text operating mode may be received over an air interface. A disadvantage of this approach is that selection of the voice-to-text operating mode may occur after the receiving party has already missed hearing a received speech message. A secondary disadvantage is that most users have a need to hear the audio in order to recognize the speaker on the other end.